Transformers for splitting
LL1570 and LL1570XL
The LL1570 is designed for splitting signals in application where large ground differences may appear, but is also very
useful as a general purpose audio transformer. By careful design, the capacative coupling between the different part of
the transformer is kept to a minimum. The three-section winding structure which is necessary for decoupling also results
in a very high bandwidth. The transformer is built up from two coils, each with primary and secondary windings
separated by electrostatic shields, and a high permeability mu-metal core. The two coil structure in combination with the
mu-metal can results in high immunity to external magnetic fields.
In the LL1570XL, the core is about 45% larger than in the LL1570, resulting in a larger level capability.
Turns ratio:
1 + 1 : 1 + 1
Pin layout (viewed from component side) and winding schematics:
Spacing between
pins
Spacing between
rows of pins
Offset of earth pin from
adjacent row:
Recommended
PCB hole diameter:
5.08 mm (0.2")
27.94 mm (1.1")
2.54 mm (0.1")
1.5 mm
LL1570
LL1570XL
Dimensions (Max. L x W x H above PCB(mm))
38 x 24 x 17
38 x 24 x 20.5
Weight:
48 g
65 g
Static resistance of each primary:
50
Ω
62
Ω
Static resistance of each secondary:
50
Ω
62
Ω
Distortion (primary level, primaries connected
0.1% @ + 6 dBU, 50 Hz
0.1% @ + 9 dBU, 50 Hz
in series, source impedance 800
Ω )
1 % < @ +16 dBU, 50 Hz
1 % < @ +19 dBU, 50 Hz
Self resonance point :
> 250 kHz
> 250 kHz
Optimum load for best square-wave response
(secondaries. in series):
2.8 k
Ω in series with 0.7 nF
2.8 k
Ω in series with 0.7 nF
Frequency response (source 600
Ω, load as
above, serial-serial connections):
10 Hz -- 200 kHz +/- 0.5 dB
10 Hz -- 200 kHz +/- 0.5 dB
Isolation winding-winding / winding-shield /
shield-shield
4 kV / 2 kV / 2 kV
4 kV / 2 kV / 2 kV
Parallel-parallel connection (1 : 1)
(e.g. mic input)
Serial-serial connection (1 : 1)
for line input or output
Parallel-serial connection (1 : 2)
(e.g. mic. input)
E1
EP
3
2
1
8
7
6
4
5
E2
+
+
E1
EP
3
2
1
8
7
6
4
5
E2
+
+
E1
EP
3
2
1
8
7
6
4
5
E2
+
+
Parallel-split connection with separate grounds (1 : 1 + 1)
3
2
1
8
7
6
4
5
E2
EP
+
+
+
E1
R980616
3
2
1
8
7
6
4
5
E1
E2
EP
Tibeliusgatan 7
International
Domestic
S-761 50 NORRTÄLJE
Phone
+46 - 176 13930
0176-13930
SWEDEN
Fax
+46 - 176 13935
0176-13935
EP = Can and core
E 2
E 1
2
1
3
4
6
5
7
8
LL1570
(top view)
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